WO1998042789A1 - Cross-linkable compounds, optionally containing mq silicon resins - Google Patents

Abstract

The invention relates to new, cross-linkable compounds containing (A1) linear organopolysiloxanes with aliphatically unsaturated hydrocarbon radicals, said organopolysiloxanes being of general formula (I) R1aR3-aSiO(R2SiO)c[R2Si-Y-SiR2O(R2SiO)c]dSiR3-bR1b, wherein R can be the same or different, and represents a monovalent, optionally halogenated hydrocarbon radical which is free of terminal aliphatic carbon-carbon multiple bonds, R1 represents a monovalent aliphatically unsaturated hydrocarbon radical, Y represents a bivalent organic radical which is free of terminal aliphatic carbon-carbon multiple bonds, a is 0 or 1, b is 0 or 1, and the sum of a + b per molecule is 1 or 2, c is a whole number to the value of 1 to 1000 and d is 0 or a whole number to the value of 1 to 10; and optionally, (A¿2?) MQ silicon resins which are soluble in (A1), on the condition that if MQ silicon resins (A2) are not used, the sum of a + b in formula (I) is 1.3 to 1.9 on average and that if MQ silicon resins (A2) are used, the sum of a + b in formula (I) is 1.0 to 1.9 on average; (B) organo-silicon compounds with si-bonded hydrogen atoms; (C) catalysts which promote the formation of an aliphatic multiple bond by si-bonded hydrogen; and optionally, (D) agents which slow down the formation of an aliphatic multiple bond by si-bonded hydrogen at room temperature.

Description

 Crosslinkable, optionally containing MQ silicone resins

Compositions

The invention relates to crosslinkable compositions containing

(A- _j _) organosilicon compounds containing aliphatic unsaturated hydrocarbon radicals and optionally (A ₂ ) MQ silicone resin, (B) organosilicon compounds containing Si-bonded hydrogen atoms, (C) the addition of Si-bonded hydrogen onto aliphatic multiple bonds, and optionally ( D) agents which delay the addition of Si-bonded hydrogen to aliphatic multiple bonds at room temperature and their use for the production of coatings which repel tacky substances.

EP-B 403890 (Bayer AG; published on March 16, 1994) or the corresponding US Pat. No. 5,077,369 and EP-A 640662 (Bayer AG; published on March 1, 1995) describe addition-crosslinking organopolysiloxane mixtures for producing adhesion-reducing coatings. The organopolysiloxanes contained in the mixtures are branched, the branching points representing trifunctional monoorganosiloxy groups, so-called T units, or tetrafunctional siloxy groups, so-called Q units. Furthermore, they have triorganosiloxy groups, so-called M units, as end groups, which contain at least one unsaturated hydrocarbon radical.

US Pat. No. 5,082,915 (Shin-Etsu Chemical Company, Ltd .; issued on January 21, 1992) describes paper coating compositions which comprise a branched organopolysiloxane with at least two Si-bonded alkenyl groups and at least one SiC-bonded siloxane side chain of the formula - (CH ₂ ) _m - (R ¹ ₂ SiO) _n -SiR ¹ ₃ per molecule, where R exn exnwertxger Hydrocarbon radical, preferably a methyl radical, m is an integer from 2 to 8 and n is an integer from 5 to 100.

Cross-linkable silicone coating compositions are known from EP-A 761 790 (Dow Corning Corporation; published March 12, 1997) which contain organopolysiloxanes with Si-bonded vinyl or higher alkenyl groups and SiC-bonded groups of the formula - (CH ₂ ) _n Si (OR) ₃ (where R is a monovalent hydrocarbon radical and n is an integer from 2 to 20).

The use of MQ silicone resins as agents for adjusting the release force in coating compositions is known from US Pat. No. 4,123,604 (Dow Corning Cooperation; issued October 31, 1978), EP-B 535 687 (Wacker-Chemie GmbH; published on January 15, June 1994) and EP-B 607 869 (Wacker-Chemie GmbH; published April 5, 1995).

The object was to provide new compositions based on organosilicon compounds which crosslink by the addition of Si-bonded hydrogen to aliphatic multiple bonds in the presence of catalysts. Another task was to provide new compositions for the production of coatings which repel tacky substances. A further object was to provide adhesive coating compositions which give abrasion-resistant coatings, i.e. adhere to the surface so that they are affected by mechanical influences, e.g. by rubbing, cannot be separated from the surface so that they can be removed with adhesive carriers, e.g. Labels, not partially peeled off and thus reduce the adhesive strength of the labels. Another object was to provide adhesive coating compositions which give tack-free, well-cured coatings. The object is achieved by the invention.

The invention relates to crosslinkable compositions containing (A- Aliphatic unsaturated hydrocarbon radicals containing linear organopolysiloxanes of the general formula

R ¹ ^ _ _a SiO (R ₂ SiO) _c [R ₂ Si-Y-SiR ₂ 0 (R ₂ SiO) _c ] _d SiR ₃ _ _b R ¹ _h (I)

where R can be the same or different, means a monovalent, optionally halogenated hydrocarbon radical having 1 to 18 carbon atoms per radical and free from terminal aliphatic carbon-carbon multiple bonds,

R represents a monovalent aliphatic unsaturated hydrocarbon radical having 2 to 14 carbon atoms per radical,

Y is a divalent organic radical that is free from terminal aliphatic carbon-carbon multiple bonds, a is 0 or 1, b is 0 or 1, and the sum a + b per molecule is 1 or 2, c is a whole Is a number from 1 to 1000 and d is 0 or an integer from 1 to 10, and optionally

(A ₂ ) MQ silicone resins which are soluble in (A-_), with the proviso that, without the use of MQ silicone resins (A ₂ ), the sum a + b in formula (I) averages 1.3 to 1, 9, and that when MQ silicone resins (A ₂ ) are used, the sum a + b in formula (I) is on average 1.0 to 1.9,

(B) organosilicon compounds containing Si-bonded hydrogen atoms,

(C) the addition of Si-bonded hydrogen to aliphatic multiple bond-promoting catalysts, and optionally

(D) retarding the addition of Si-bonded hydrogen to aliphatic multiple bonds at room temperature

Medium. The invention further provides a process for the production of coatings which repel tacky substances by applying crosslinkable compositions comprising (A _j _) aliphatically unsaturated hydrocarbon radicals aufwei- send linear organopolysiloxanes of the general formula

R ^ - ^. ^ IO (R ₂ SiO) _c [R ₂ Si-Y-SiR ₂ 0 (R ₂ SiO) _c ] _d SiR ₃ _ _b R ¹ _b (I)

where R, R, Y, a, b, c and d have the meaning given above, and optionally

(A ₂ ) MQ silicone resins which are soluble in (A- _j _), with the proviso that, without the use of MQ silicone resins (A ₂ ), the sum a + b in formula (I) averages 1.3 to 1 , 9, and that when MQ silicone resins (A ₂ ) are used, the sum a + b in formula (I) is on average 1.0 to 1.9, (B) organosilicon compounds containing Si-bonded hydrogen atoms, (C) the Addition of Si-bonded hydrogen to aliphatic multiple bond-promoting catalysts, and optionally

(D) the addition of Si-bonded hydrogen to aliphatic multiple bonds at room temperature retarding agents on the surfaces to be made repellent and subsequent curing of the crosslinkable composition.

The invention, aliphatically unsaturated hydrocarbon radicals having linear organopolysiloxanes (A _j _) loading sit preferably a viscosity from 5 to 20,000 mm / s at 25 ° C, preferably 20 to 1 000 mm ² / s at 25 ° C, particularly preferably 20 to 500 mm ² / s at 25 ° C.

The organopolysiloxanes according to the invention preferably have iodine numbers between 1 and 80, preferably 4 and 15, the iodine number being the one added to the double bond indicates the amount of iodine consumed in grams per 100 grams of organopolysiloxane used according to the invention.

Examples of radicals R are alkyl radicals, such as the methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert. -Butyl, n-pentyl, isopentyl, neopentyl and the tert. Pentyl radical, hexyl radicals, such as the n-hexyl radical, heptyl radicals, such as the n-heptyl radical, octyl radicals, such as the n-octyl radical and iso-octyl radicals, such as the 2, 2, 4-trimethylpentyl and 2-ethylhexyl radical, nonyl radicals , such as the n-nonyl radical, decyl radicals, such as the n-decyl radical, dodecyl radicals, such as the n-dodecyl radical, tetradecyl radicals, such as the n-tetradecyl radical, hexadecyl radicals, such as the n-hexadecyl radical and octadecyl radicals, such as the n-octadecyl radical Cycloalkyl radicals, such as cyclopentyl, cyclohexyl and 4-ethylcyclohexyl radical, cycloheptyl radicals, norbornyl radicals and methylcyclohexyl radicals, aryl radicals, such as the phenyl, biphenylyl, naphthyl and anthryl and phenanthryl radical; Alkaryl residues, such as o-, m-, p-tolyl residues, xylyl residues and ethylphenyl residues; Aralkyl radicals, such as the benzyl radical, and the α- and the β-phenylethyl radical.

The radical R is preferably the methyl radical.

Examples of halogenated radicals R are haloalkyl radicals, such as the 3,3,3-trifluoro-n-propyl radical, the 2, 2, 2, 2 ', 2', 2 '-hexafluoro-isopropyl radical and the heptafluoroisopropyl radical, and halo-aryl radicals, like the o-, m- and p-chlorophenyl radical.

Y is preferably a divalent hydrocarbon radical which can contain one or more separate oxygen atoms.

Examples of radicals Y are those of the formula -CH ₂ CH ₂ -, -CH (CH ₃ ) -, - (CH ₂ ) _Λ ~ ι ~ (CH) c ~ ~ (CH ₂ ) g -, - (CH ₂ ) g -, - (CH ₂ ) i _Q ~ # - (CH ₂ ) ₁₂ -, - (CH ₂ ) ₃ 0 (CH ₂ ) ₃ -, 1,3- (CH ₂ CH ₂ ) ₂ (C ₆ H ₄ ), 1,4- (CH ₂ CH ₂ ) ₂ (C ₆ H ₄ ), 1,3- (CH ₂ CHCH ₃ ) ₂ (C ₆ H ₄ ), the radicals of the formula -CH ₂ CH ₂ -, -CH (CH ₃ ) -, - (CH ₂ ) g-, - (CH ₂ ) _g - are preferred and the rest of the formula -CH ₂ CH ₂ - is particularly preferred. The radicals R preferably have a terminal double bond. Examples of radicals R are vinyl, allyl, 3-butenyl, 5-hexenyl, 7-0ctenyl, 9-decenyl, 11-dodecenyl, 3-allyloxypropyl, 2- (3-vinylphenyl) ethyl - And the 2- (4-vinylphenyl) ethyl radical, the vinyl and the 5-hexenyl radical being preferred and the vinyl radical being particularly preferred.

If MQ silicone resins (A ₂ ) are not used, the organopolysiloxanes (A - ** _) have on average 65 to 95 mol% of radicals R, preferably ω-alkenyl end groups, or 35 to 5 mol% as end groups Residues R, preferably methyl end groups), which corresponds to an average sum a + b of 1.3 to 1.9. The sum a + b is preferably on average 1.3 to 1.8.

If MQ silicone resins (A ₂ ) are also used, the organopolysiloxanes (A- as end groups have an average of 50 to

95 mol% of radicals R, preferably ω-alkenyl end groups, (or as end groups 50 to 5 mol% of radicals R, preferably methyl end groups), which corresponds to an average sum a + b of 1.0 to 1.9. The sum a + b is preferably on average 1.0 to 1.5, in particular 1.1 to 1.4.

A mixture of different organopolysiloxanes (A-_) is preferably used in the compositions according to the invention.

Preferably c is an integer from 10 to 300, more preferably 20 to 150.

Preferably d is 0 or an integer from 1 to 3, d is preferably 0.

Processes for the preparation of linear organopolysiloxanes of the formula (I) with d equal to 0 are known to the person skilled in the art. A preferred method is acid catalyzed Equilibration of polydialkylsiloxanes with alkyl end groups with polydialkylsiloxanes with ω-alkenyl end groups.

Linear organopolysiloxanes of the formula (I), where d is an integer from 1 to 10, and processes for their preparation are described in US Pat. No. 5,057,549 or the corresponding DE-A 39 14 896.

MQ silicone resins (A ₂ ) which are optionally used are those from units of the general formula

R ₃ Si0 _1/2 (IV), R ¹ R ₂ Si0 _1/2 (V) and Si0 ₂ (VI),

where R and R have the meaning given above, used.

The ratio of M units of the formula (IV) and (V) to Q units of the formula (VI) is preferably 0.5 to 1.5, preferably 0.5 to 1.0. The ratio of saturated M units of the formula (IV) to unsaturated M units of the formula (V) is preferably 5 to 20, preferably 5 to 10.

The MQ silicone resins may contain small amounts of SiO ₂ T units of the formula RSi0 _3/2 and D units of the formula R.

Processes for the preparation of the MQ silicone resins (A ₂ ) are described in the aforementioned EP-B 535 687 and therefore belong to the disclosure content of this application.

If MQ silicone resins (A ₂ ) are also used, the MQ silicone resins (A ₂ ) are used in amounts of preferably 40 to 60% by weight, preferably 50 to 55% by weight, in each case based on the total weight of the constituents (A- ^) and (A ₂ ) used. High MQ silicone resin concentrations lead to greatly increased viscosities, so that when using more than 60% by weight MQ silicone resin (A ₂ ) it is usually no longer possible to do without the addition of solvents. The use of MQ silicone resins (A ₂ ) has the advantage that the release force of the adhesive coatings can be adjusted.

In the crosslinkable compositions according to the invention, the same organopolysiloxanes containing Si-bonded hydrogen atoms can also be used as constituent (B), which are used in all previously known compositions of aliphatic unsaturated hydrocarbon radicals, such as organopolysiloxanes containing vinyl groups, organopolysiloxanes containing Si-bonded hydrogen atoms and the addition of Si-bonded hydrogen to aliphatic multiple bond-promoting catalysts could be used.

The organopolysiloxanes (B) preferably contain at least 3 Si-bonded hydrogen atoms.

Organopolysiloxanes composed of units of the formula are preferably used as component (B)

H R SiO: n: e f 4 * (e + f)

where R has the meaning given above, e 0 or 1, f 0, 1, 2 or 3 and the sum e + f is not greater than 3,

preferably those of the formula

H _g R ₃ _ _g SiO (SiR ₂ 0) _k (SiRHO) ₁ SiR ₃ _ _g H _g (III)

where R has the meaning given above, g 0 or 1, k O or an integer from 1 to 100 and

1 is O or an integer from 1 to 100, or organosilicon compounds containing Si-bonded hydrogen atoms, as described in the German application with the applicant's file number 196 02 663.6 or mixtures of the above-mentioned organopolysiloxanes and organosilicon compounds.

Examples of organopolysiloxanes (B) are, in particular, copolymers of dimethylhydrogensiloxane, methylhydrogensiloxane, dimethylsiloxane and trimethylsiloxane units, copolymers of trimethylsiloxane, dimethylhydrogensiloxane and methylhydrogensiloxane units, copolymers of trimethylsiloxane and dimethyl units, methylethylsiloxane, dimethyl units Trimethylsiloxane units, copolymers of methylhydrosiloxane, diphenylsiloxane and trimethylsiloxane units,

Copolymers of methylhydrosiloxane, dimethylhydrosiloxane and diphenylsiloxane units, copolymers of methylhydrosiloxane, phenylmethylsiloxane, trimethylsiloxane and / or dimethylhydrogensiloxane units, copolymers of methylhydrogensiloxane, dimethylsiloxane

Diphenylsiloxane, trimethylsiloxane and / or dimethylhydrosiloxane units and copolymers of dimethylhydrosiloxane, trimethylsiloxane, phenylhydrosiloxane, dimethylsiloxane and / or phenylmethylsiloxane units.

Methods for producing organopolysiloxanes (B), including organopolysiloxanes (B) of the preferred type, are generally known.

Organosilicon compounds (B) are preferably used in amounts of 0.5 to 6, preferably 1 to 3, particularly preferably 1.2 to 2.5 gram atom of Si-bonded hydrogen πe mole radical R in the organopolysiloxanes (A) containing aliphatic unsaturated hydrocarbon radicals.

The catalysts (C) which promote the attachment of Si-bonded hydrogen to aliphatic multiple bonds can also be the same in the compositions according to the invention Catalysts are used which could also be used in the previously known compositions for crosslinking organosilicon compounds containing aliphatic multiple bonds with compounds which contain Si-bonded hydrogen to promote crosslinking. The catalysts (C) are preferably a metal from the group of platinum metals or a compound or a complex from the group of platinum metals. Examples of such catalysts are metallic and finely divided platinum, which can be on supports, such as silicon dioxide, aluminum oxide or activated carbon, compounds or complexes of platinum, such as platinum halides, for example PtCl ₄ , H ₂ PtClg * 6H ₂ 0, Na ₂ PtCl ₄ * 4H ₂ 0, platinum-olefin complexes, platinum-alcohol complexes, platinum-alcohol complexes, platinum-ether complexes, platinum-aldehyde complexes, platinum-ketone complexes, including reaction products of H ₂ PtClg * 6H ₂ 0 and cyclohexanone, platinum-vinylsiloxane complexes, such as

Platinum-1,3-divinyl-1,3,3-tetramethyldisiloxane complexes with or without content of detectable inorganic halogen, bis- (gamma-picolin) -platinum dichloride, trimethylene-dipyridineplatinum dichloride, dicyclopentadiene-platinum dichloride, dimethylsulfoxydethylene II) dichloride, cyclooctadiene platinum dichloride, norbornadiene platinum dichloride, gamma-picoline platinum dichloride, cyclopentadiene platinum dichloride, and reaction products of platinum tetrachloride with olefin and primary amine or secondary amine or primary and secondary amine according to US-A 4,292,434, as the reaction product of platinum tetrachloride dissolved in 1-octene with sec. -Butylamine, or ammonium-platinum complexes according to EP-B 110 370.

Catalyst (C) is preferably used in amounts of 5 to 500 ppm by weight (parts by weight per million parts by weight), in particular 10 to 200 ppm by weight, in each case calculated as elemental platinum metal and based on the total weight of the organopolysiloxanes' (A) and (B) used.

As agents that retard the attachment of Si-bonded hydrogen to aliphatic multiple bonds at room temperature, So-called inhibitors (D), all inhibitors can also be used in the compositions according to the invention, if any, that could previously also be used for the same purpose. Examples of inhibitors are 1, 3-divinyl-1, 1, 3, 3-tetramethyldisiloxane, benzotriazole, dialkylformamides, alkylthioureas, methylethylketoxime, organic or organosilicon compounds with a boiling point of at least 25 ° C. at 1012 mbar (abs.) And at least one aliphatic triple bond according to US Pat. No. 3,445,420, such as 1-ethynylcyclohexan-1-ol, 2-methyl-3-butyn-2-ol,

3-methyl-1-pentin-3-ol, 2, 5-dimethyl-3-hexin-2, 5-diol and 3, 5-dimethyl-1-hexin-3-ol, 3, 7-dimethyl-oct- 1-in-6-en-3-ol, inhibitors according to US Pat. No. 2,476,166, such as a mixture of dialyl maleinate and vinyl acetate, and inhibitors according to US Pat. No. 4,504,645, such as maleic acid monoesters.

The inhibitor (D) is preferably used in amounts of 0.001 to 10% by weight, based on the total weight of the organopolysiloxanes (A) and (B).

Examples of further constituents which can be used in the compositions according to the invention are solvents, adhesion promoters and pigments.

The solvents which may be used in the compositions according to the invention can be the same solvents which are used in the compositions known hitherto from organopolysiloxanes containing aliphatic unsaturated hydrocarbon radicals, organopolysiloxanes containing Si-bonded hydrogen and the addition of Si-bonded hydrogen to aliphatic double bond-promoting catalysts could. Examples of such solvents are gasolines, e.g. B. alkane mixtures with a boiling range of 80 ° C to 110 ° C at 1012 mbar (abs.), N-heptane, benzene, toluene and xylenes, halogenated alkanes with 1 to 6 carbon atoms, such as methylene chloride, trichlorethylene and perchlorethylene, ethers, such as Di-n-butyl ether, esters such as ethyl acetate and ketones such as methyl ethyl ketone and cyclohexanone. If organic solvents are also used, they are expediently used in amounts of 10 to 95% by weight, based on the weight of the organopolysiloxanes (A) containing aliphatic unsaturated hydrocarbon radicals.

The order in which components (A), (B), (C) and, if appropriate, (D) are mixed is not critical, but in practice it has proven useful to use component (C), that is to say the catalyst, the mixture of the others Add ingredients last.

The compositions according to the invention are preferably crosslinked at 50 to 150 ° C., preferably at 80 to 150 ° C. As energy sources for the crosslinking by heating, stoves, for. B. convection drying cabinets, heating channels, heated rollers, heated plates or heat rays of the infrared range used.

In addition to heating, the compositions according to the invention can also be crosslinked by irradiation with ultraviolet light or by irradiation with UV and IR light. The ultraviolet light used is usually one with a wavelength of 253.7 nm. There are a large number of lamps on the market which emit ultraviolet light with a wavelength of 200 to 400 nm and which preferentially emit ultraviolet light with a wavelength of 253.7 nm.

The compositions according to the invention have the advantage that coatings which are resistant to abrasion are obtained after crosslinking. Furthermore, tack-free and well-cured coatings are obtained, so that the adhesive strength of the adhesives which come into contact with the coatings is practically not impaired.

The application of the compositions according to the invention to the surfaces to be rendered repellent can be used in any manner for the production of coatings from liquid Suitable substances and well known manner take place, for example by dipping, brushing, pouring, spraying, rolling, printing, z. B. by means of an offset engraving coating device, knife or knife coating or by means of an air brush.

The surfaces to be rendered repellent, which can be treated in the context of the invention, can be any surfaces which are solid at room temperature and 1012 mbar (abs.). Examples of such

Surfaces are those of paper, wood, cork and plastic films, e.g. B. polyethylene films or polypropylene films, woven and non-woven cloth made of natural or synthetic fibers or glass fibers, ceramic objects, glass, metals, paper coated with polyethylene and cardboard, including those made of asbestos. The polyethylene mentioned above can each be high, medium or low pressure polyethylene. Paper can be inferior papers, such as absorbent papers, including raw kraft paper with a weight of 60 to 150 g / m, not pretreated with chemicals and / or polymeric natural substances, unsized papers, papers with low paper Grinding grade, wood-containing papers, non-satinized or non-calendered papers, papers that are smooth on one side due to the use of a dry smoothing cylinder during their production without further complex measures and are therefore referred to as "one-sided machine-smooth papers", uncoated papers or papers made from paper waste , so-called waste papers. The paper to be treated according to the invention can of course also be high-quality paper types, such as low-suction papers, sized papers, papers with a high degree of grinding, wood-free papers, calendered or satin-coated papers, glassine papers, parchmentized papers or pre-coated papers, act. The cardboards can also be of high or low quality. The compositions according to the invention are suitable, for example, for the production of release papers, cover papers and idler papers, including idler papers, which are used in the production of e.g. B. cast or decorative films or foams, including those made of polyurethane, are used. The compositions according to the invention are furthermore suitable, for example, for the production of separating, covering, and follower cardboards, foils and wipes, for the finishing of the rear sides of self-adhesive tapes or self-adhesive foils or the labeled sides of self-adhesive labels. The compositions according to the invention are also suitable for the finishing of packaging material, such as that of paper, cardboard boxes, metal foils and barrels, e.g. As cardboard, ^' plastic, wood or iron, the or for storage and / or transport of sticky goods, such as adhesives, sticky foods, for. B. cakes, honey, candy and meat; Bitumen, asphalt, greased materials and raw rubber, is determined, or are. Another example of the use of the compositions according to the invention is the equipment of carriers for the transfer of pressure-sensitive adhesive layers in the so-called

"Transfer process".

The compositions according to the invention are suitable for producing the self-adhesive materials connected to the release paper both by the off-line method and by the in-line method. In the off-line process, the silicone composition is applied to the paper and crosslinked, then, in a subsequent step, usually after the release paper has been wound up on a roll and after the roll has been stored, an adhesive film which, for example, lies on a label face paper , applied to the coated paper and the composite is then pressed together. In the in-line process, the silicone composition is applied to the paper and crosslinked, the silicone coating is coated with the adhesive, the label face paper is then applied to the adhesive and the composite is finally pressed together.

Preparation of the organopolysiloxanes (A): Polymer I:

A mixture of 1200 g of an α, ω-divinylpolydimethylsiloxane with a viscosity of 217 mm / s at 25 ° C and 100 g of a methyl-terminated polydimethylsiloxane with a viscosity of 346 mm / s at 25 ° C is mixed with 50 ppm phosphonitrile chloride at 125 ° C equilibrated to constant viscosity. The catalyst is neutralized, the crude product is filtered and freed from volatile by-products at 160 ° C. and 3 hPa. A clear oil with a viscosity of 180 mm / s at 25 ° C. and an iodine number of 6.9 is obtained. The product contains an average of 94 mol% vinyl end groups (a + b = 1.88).

Polymer II:

The analogous repetition of Example 1 with only 700 g of the α, ω-divinylpolydimethylsiloxane gives a polymer with a viscosity of 204 mm / s at 25 ° C. and an iodine number of 6.7. The product contains an average of 90 mol% vinyl end group (a + b = 1.80).

Polymer III:

The analogous repetition of Example 1 with only 500 g of the α, ω-divinylpolydimethylsiloxane gives a polymer with a viscosity of 214 mm / s at 25 ° C. and an iodine number of 6.0. The product contains an average of 86 mol% vinyl end groups (a + b = 1.72).

Polymer IV:

30 g of 1,3-di (5-hexenyl) tetramethyldisiloxane are equilibrated with 1350 g of a methyl-terminated polydimethylsiloxane with an average chain length of about 900 siloxy units, with catalysis by phosphorus nitride chloride (100 ppm). Working up as in Example 1 gives a clear siloxane polymer with a viscosity of 380 mm / s at 25 ° C. and an iodine number of 4.1. The polymer contains an average of 83 mol% of 5-hexenyl groups (a + b = 1.66). Polymer V:

600 g of a siloxane polymer of average composition (HMe ₂ Si0 _{1/2) -]} _ ₈ (Me ₃ Si0 ₁ /) _{n 2} (Me ₂ SiO) _4g are mixed with 24 g of 1,5-hexadiene and about 60 ° C warmed. 15 mg of H ₂ PtClg are added. 6H ₂ 0 (dissolved in approx. 2 ml isopropanol), after which the internal temperature increases by approx. 22 ° C. Volatile components are removed at 130 ° C and 3 hPa. The product obtained has a viscosity of 182 mm / s at 25 ° C. and an iodine number of 6.3. It contains 82 mol% 5-hexenyl groups (a + b = 1.64).

Polymer VI:

Example 1 is repeated by using 86 g of a methyl-terminated polydimethylsiloxane with a viscosity of ₂ 20 mm / s at 25 ° C. instead of 100 g of the methyl-terminated polydimethylsiloxane. After working up, a clear, colorless polymer with a viscosity of

108 mm ² / s at 25 ° C and an iodine number of 7.9. The product (VI) contains an average of 77 mol% of vinyl end groups (a + b = 1.54).

Polymer VII:

250 g of an α, ω-divinylpolydimethylsiloxane with an average chain length of 29 siloxy units are equilibrated with 400 g of a methyl-terminated polydimethylsiloxane with a viscosity of 5000 mm / s at 25 ° C. with the catalysis of 50 ppm of phosphonitrile chloride at 145 ° C. Working up according to Example 1 gives a clear polymer (VII) with a viscosity of 112 mm / s at 25 ° C. and an iodine number of 8.7. It contains an average of 90 mol% vinyl end groups (a + b = 1.80).

Polymer VIII:

Example 7 is repeated with 500 g of a methyl-terminated polydimethylsiloxane with a viscosity of 1000 mm ² / s at 25 ° C. instead of 5000 mm ² / s. The product viscosity (VIII) is now 109 mm / s at 25 ° C with an iodine number of 7.6. It contains an average of 83 mol% of vinyl end groups. (a + b = 1.66). Comparative polymer 1:

Example 8 is repeated with 700 g of a methyl-terminated

₂

Polydimethylsiloxane with a viscosity of 205 mm / s at 25 ° C

2 instead of the polymer at 5000 mm / s. Equilibration and processing result in a clear polymer with a viscosity of 97 mm / s at 25 ° C and an iodine number of 6.6. The product contains an average of 55 mol% vinyl end groups per molecule (a + b = 1.10).

Comparative polymer 2:

= α, ω-divinylpolydimethylsiloxane with 98 siloxane units (= chain length 98)

Examples 1 to 3 and Comparative Experiments 1 and 2:

The following formulations (Table 1) are produced from components A, B, C and D:

(A) Alkenyl-functional siloxane: polymer VI, VII, VIII or comparative polymer 1 and 2

(B) H-siloxane crosslinking agent: polyhydrogenmethylsiloxane (methyl-terminated) with 1.54% by weight Si-bonded hydrogen

(C) catalyst:

Platinum-1,3-divinyl-1,3,3-tetramethyldisiloxane complex dissolved in α, ω-divinylpolydimethylsiloxane (1% Pt content) (so-called Karstedt catalyst according to US Pat. No. 3,775,452) (D) inhibitor: 1 -Ethynylcyclohexanol

The components are mixed in the order (A) + (D) + (B) + (C). - 1y

Table 1

The ratio of Si-bonded hydrogen to H ₂ C = CH groups is 2.0. All formulations contain 0.25% 1-ethynylcyclohexanol and have gel times of> 72 h.

The mixtures are worked onto a polyester film in a layer thickness of approx. 4 μm and hardened in a convection oven at 85 ° C for 20 seconds. The results are summarized in Table 2.

Table 2:

Separating force extract [cN / cm]

[% By weight] A 7475 K 7476 T 154 maintenance [%]

Example 1 5.9 18 11 9> 100

Example 2 11.6 16 8 8> 100

Example 3 6.5 16 9 8> 100

Comparative silicone coating is soft and sticky try 1

Comparative 4.1 8 13 4> 100 try 2

Extractable fractions are considered to be non-crosslinked components (extractant: methyl isobutyl ketone) The separating forces compared to the three adhesive tapes and the preservation of the separating force were printed in accordance with FINAT 10 and 11 in "Suppliers and Users Technical Manual", June 1980, pages 21 to 24, using commercially available self-adhesive (pressure sensitive) 2.5 cm wide adhesive tapes "Tesafilm A 7475", "Tesafilm K 7476" and "Tesafilm T 154" (Fa. Beiersdorf AG, Hamburg, FRG; the word part "Tesa" is a registered trademark).

The comparison shows that a too low content of reactive alkenyl groups (<65 mol%) in the linear organopolysiloxane (A) leads to inadequate curing (comparative experiment 1).

The quality of the substrate adhesion of the cured films is determined against several substrates in the abrasion test. To determine the abrasion, the coated substrates are stretched with the thumb and forefinger. Then, with vigorous pressure, the finger of the other hand is rubbed back and forth several times on the tightened substrate. If the silicone film adheres poorly to the substrate surface, part of the silicone coating is rubbed off. The abrasion is rated according to the strength with the marks 1-6, whereby a completely undamaged surface is rated with the mark 1 and a complete abrasion with the mark 6.

The results are summarized in Table 3.

Table 3:

Abrasion assessment: immediately (after 5 days) Although comparative experiment 2 also showed good curing, the formulations according to the invention are considerably superior in abrasion behavior.

Example 4:

MQ resin formulations are prepared in various concentrations from the following components:

A * _j _ α, ω -divinyldimethylpolysiloxane from 1.2 mol vinyldimethylsiloxy, 0.8 mol trimethylsiloxy and 27 mol dimethylsiloxy units, ie 60 mol% of the end groups are vinyl groups

(a + b = 1.2).

A ₂ MQ resin consisting of (CH _{3) 3} Si0 _1/2 units (M - * _)

CH ₂ = CH (CH _{3) 2} Si0 _1/2 units (M ₂₎ and Si0 ₂ units (Q) wherein the ratio of the sum of the units M _L + M ₂ to Q units is 0.7 and the ratio from M - ^ - units to M ₂ units is 1: 7.3 (1400g / C = C double bond).

B) H-siloxane from methylhydrogensiloxane and trimethylsiloxane units with 15.4 g Si-bonded hydrogen / kg C) Platinum-1,3-divinyl-l, 1,3,3-tetramethyldisiloxane complex

(so-called Karstedt catalyst according to US-A 3,775,452) dissolved in α, ω-divinyldimethylpolysiloxane with a viscosity of 1000 mm ² / s at 25 ° C (1.0% Pt content)

D) 1-ethynylcyclohexanol.

The ready-to-use, freshly prepared compositions contain 2.5 g of Si-bonded hydrogen per mole of double bond. They are squeegee with a 4 μm layer of glass on several substrates and hardened at 85 ° C in a convection oven. Then the abrasion behavior is checked.

The quality of the substrate adhesion of the cured films is determined against several substrates in the abrasion test. To determine the abrasion, the coated substrates are stretched with the thumb and forefinger. Then, with vigorous pressure, the finger of the other hand is rubbed back and forth several times on the tightened substrate. If the silicone film adheres poorly to the substrate surface, part of the silicone coating is rubbed off. The abrasion is assessed according to the strength with the marks 1-6, whereby a completely undamaged surface is rated with the mark 1 and a complete abrasion with the mark 6.

The results are summarized in Tables 4 and 5.

Table 4:

Tabelle 5

Table 5

1 = no abrasion - 6 = complete abrasion

The coatings adhere perfectly to all substrates,

Comparative experiment 3:

A commercially available resin formulation (CRA 17 available from Wacker-Chemie GmbH) is mixed 1: 1 with an α, ω-divinyldimethylpolysiloxane with a viscosity of 180 mm / s at 25 ° C and with crosslinker (B) to give an identical SiH / C = C ratio as described in Example 4, mixed. Components (C) and (D) are added in identical concentrations as described in Example 4.

The freshly prepared composition is squeegee with a glass rod in a layer thickness of 4 μm on several substrates and hardened at 85 ° C in a convection oven. The substrate adhesion is determined in the abrasion test as described in Example 4. The results are summarized in Tables 6 and 7. Table 6:

Table 7

In almost all cases, substrate adhesion is very poor and the coating is unusable.

Claims

claims 1. Containing crosslinkable compositions (A * _] _) aliphatic unsaturated hydrocarbon radicals containing linear organopolysiloxanes of the general formula R ¹ _a R ₃ - _a ^{si0 (} R2 ^Si0) c [R2 ^{si "Y-SiR} 2 ° ^(R 2 ^Si ° ⁾ c- ¹ d ^SiR 3 -b ^Rl b ^(i: where R can be the same or different, means a monovalent, optionally halogenated hydrocarbon radical having 1 to 18 carbon atoms per radical and free from terminal aliphatic carbon-carbon multiple bonds, R represents an exogenous aliphatic unsaturated hydrocarbon radical having 2 to 14 carbon atoms per radical, Y is a divalent organic radical that is free from terminal aliphatic carbon-carbon Multiple bonds means a is 0 or 1, b is 0 or 1, and the sum a + b per molecule is 1 or 2, c is an integer from 1 to 1000 and d is 0 or an integer in value from 1 to 10, and optionally (A ₂ ) MQ silicone resins which are soluble in (A- _j _), with the proviso that without the use of MQ silicone resins (A ₂ ) the sum a + b in formula ( I) is 1.3 to 1.9 on average, and that when MQ silicone resins (A ₂ ) are also used, the total a + b in formula (I) is 1.0 to 1.9 on average, (B) organosilicon compounds containing Si-bonded hydrogen atoms, (C) the addition of Si-bonded hydrogen to aliphatic multiple bond-promoting catalysts, and optionally (D) Agents that retard the attachment of Si-bonded hydrogen to aliphatic multiple bonds at room temperature. 2. Crosslinkable compositions according to claim 1, characterized in that R is a vinyl radical. 3. Crosslinkable compositions according to claim 1 or 2, characterized in that d is 0. 4. Crosslinkable compositions according to claim 1, 2 or 3, characterized in that as MQ silicone resins (A ₂ ) those from units of the general formula R * ^ _j SiO (IV), R ¹ R ₂ Si0 _1/2 (V) and Si0 ₂ (VI), wherein R and R have the meaning given in claim 1, and the ratio of M units of the formula (IV) and (V) to Q units of the formula (VI) is 0.5 to 1.5 and the ratio of saturated M units of the formula (IV) to unsaturated M units of the formula (V) is 5 to 20 can be used. 5. A process for the production of coatings which repel tacky substances by applying crosslinkable compositions according to one of claims 1 to 4 to the surfaces to be rendered repellent and subsequent curing of the crosslinkable composition.